1. Field of the Invention
The present invention relates to a torque transmitting apparatus, and more particularly to a torque transmitting apparatus for a motor vehicle, wherein the apparatus includes a fluid coupling, such as a Fxc3x6ttinger clutch or a torque converter.
2. Description of the Related Art
Fluid couplings for motor vehicles include at least one pump impeller non-rotatably affixed to a drive shaft of a drive unit, at least one turbine wheel non-rotatably affixed to the input shaft of a power train to be driven, as well as, if necessary, at least one stator arranged between the impeller and the turbine, at least one housing receiving the impeller and the turbine, and at least one active torsional-vibration damper mounted between the drive shaft and the input shaft.
Such torque transmitting systems are especially known for use with multi-speed automatic transmissions, and a purpose of the present invention is to improve such systems, in particular their vibration damping effectiveness. Moreover, an improved damping design should be simpler and less costly to manufacture. The implementation of the control elements should be simple and compatible with the torque transmitting systems of the state of the art.
This problem is solved in a torque transmitting apparatus in accordance with the present invention, in particular one for a motor vehicle that includes a fluid coupling, such as a Fxc3x6ttinger clutch or a torque converter. The apparatus includes at least one impeller non-rotatably affixed to a drive shaft of a drive unit, at least one turbine non-rotatably affixed to an input shaft of a power train to be driven, as well as at least one stator mounted between the impeller and the turbine. The apparatus also includes at least one housing receiving the impeller and the turbine, and at least one active torsional-vibration damper mounted between the drive shaft and the input shaft, wherein the at least one torsional-vibration damper is arranged in the path of the flow of power between the drive shaft and the impeller.
In this torque transmitting apparatus the impeller can be rotatable relative to the housing.
In this torque transmitting apparatus the torsional-vibration damper can be arranged in the path of the flow of power and between the housing and the impeller.
In this torque transmitting apparatus the torsional-vibration damper can be mounted inside the housing.
In this torque transmitting apparatus the torsional-vibration damper can be mounted axially between the turbine and a housing wall facing the drive unit.
Moreover the torque transmitting apparatus of the invention allows mounting the torsional-vibration damper directly radially within an external periphery of the housing, and a controllable lockup clutch can be operational between the impeller and the housing or between a shell of the impeller and the housing. Further, the lockup clutch can be in the form of a piston non-rotatably supported on the housing but being axially displaceable, the piston being capable of frictionally engaging a component of the impeller.
In this torque transmitting apparatus a controllable lockup clutch can be mounted between the housing and the input shaft. When the lockup clutch is locked, at least one torsional-vibration damper can also be operative between the housing and the input shaft.
In the torque transmission system in accordance with the invention, the input element of the torsional-vibration damper can be joined directly to the housing or be integral with it. The output element of the torsional-vibration damper can be in the form of a flange that includes a frictional engagement surface for the plunger of the lockup clutch. The inner circumference of the flange can be radially beaded outward in order to provide a conical frictional engagement surface.
In a further embodiment of the invention, the output element of the torsional-vibration damper can be provided directly as an axial attachment to the impeller, preferably at its outer periphery. Furthermore, an annular flange to frictionally engage the plunger of the lockup clutch can be provided radially inward on the attachment. Additionally, the annular flange can be conical and can be arranged to face inwardly.
In accordance with the invention, frictional coatings can be arranged on the plunger or on the surface of the plunger that contacts the housing to provide the frictional engagement function.
To improve vibration behavior, the housing can be in the form of a primary inertial weight that is rotatable relative to a secondary inertial weight associated with the impeller to oppose the effect of the torsional-vibration damper. The secondary inertial weight can be supplemented by at least the mass of the turbine when the lockup clutch is engaged.
The at least one torsional-vibration damper can include circumferentially-distributed energy accumulator, which are effective at least in the circumferential direction and which can be in the form of short compression coil springs, and which preferably are mounted radially inside the largest axial dimension of the turbine. Alternatively, they can preferably be formed of pre-bent coil springs mounted adjacent the circumference of the assembly and, regarding their length as compared with the radius of the circumference of the assembly, they run over a comparable or larger arc of a circle and are mounted radially outside the largest axial turbine dimension, preferably directly inside the outer periphery of the housing.